In an effort to reduce overall vehicle weight, aluminum is proposed to be used for both structural and exterior body panels. Aluminum roof panels on large SUV vehicles are susceptible to thermal deflections during the electro-coat and paint bake processes. Thinner gauge material is preferred to be used on roof panels which increases the rate and magnitude of thermal deflection compared to supporting roof bows that are formed of thicker gauge material. The difference in thermal deflection between the roof panel and supporting roof bows causes an increase in the gap between these parts.
Anti-flutter material provided as a tape or mastic paste is applied to bows that support the roof panel during assembly prior to electro-coating and the paint bake operations. The anti-flutter material supports the roof panel after curing where the roof panel is joined to the roof bows. Anti-flutter material has a low modulus of elasticity and does not add strength or stiffness to the joint between the roof panel and the roof bows but instead expands to a limited extent to compensate for the gap caused by differential between the thermal deflection of the roof panel and the roof bows. Generally, the gap between the roof panel and roof bows in the finished vehicle should be less than 6 millimeters to assure proper adhesion that, in turn, minimizes flutter of the roof panel when the vehicle is driven.
This disclosure is directed to solving the above problems and other problems as summarized below.